JP5072238B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to a technique of an image forming apparatus having a borderless printing mode.

  Image forming apparatuses such as printers, copiers, and facsimile machines using an electrophotographic process form a developer image formed on a photosensitive drum as a first image carrier on a recording material such as recording paper or an OHP sheet. . In addition, the color image forming apparatus performs primary transfer onto a second image carrier having a rotating belt shape to sequentially transfer multi-color toner (developer), and then transfers the second image from the second image carrier to a recording material. Next transfer.

  In the case where the developer image is smaller than the size of the recording material, that is, in printing with a margin in which a margin is formed at the end of the recording material, the developer image formed on the second image carrier is transferred to the recording material. All toner contacts the recording material during transfer. For this reason, the toner formed on the second image carrier does not adhere to the transfer roller or the rotating belt disposed opposite to the transfer portion. However, in marginless printing in which an image is formed on the entire recording material so that no margin is generated at the end of the recording material, the image forming apparatus does not generate a margin even if the position of the recording material is slightly deviated from the normal position. Thus, a developer image larger than the area of the recording material is formed. For this reason, the toner formed beyond the area of the recording material can adhere to the transfer roller and the rotating belt during transfer to the recording material. Further, the toner adhering to the transfer roller and the rotating belt may be re-transferred to the back surface of the recording material, which causes back stain. Further, the toner formed beyond the area of the recording material is not transferred to the recording material and remains on the second image carrier as waste toner. Therefore, in the current image forming apparatus, a technique for removing such waste toner or reducing the waste toner is required.

  In particular, an image forming apparatus capable of borderless printing often includes a cleaning unit that cleans residual toner adhering to a transfer roller and a rotating belt. For example, such an image forming apparatus includes a secondary transfer waste toner container that scrapes off residual toner on a transfer roller with a blade and stores the removed waste toner. When the image forming apparatus provided with the secondary transfer waste toner container continues to print even after the waste toner amount becomes full, the waste toner overflows and soils the image forming apparatus. Stops printing.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique that allows a user to accurately grasp the amount of accumulated waste toner by notifying the transition of the amount of accumulated waste toner at any time at low cost.

  Patent Document 2 discloses a technique in which the printed material is adhered to a sheet larger than the printed material, an image larger than the size of the printed material and smaller than the sheet is formed, and the printed material is peeled off from the sheet after printing. As a result, the waste toner is prevented from remaining on the second image carrier (intermediate transfer member).

Patent Document 3 discloses a technique for cutting a peripheral edge of a sheet after printing using a sheet dedicated to borderless printing. This suppresses the waste toner from remaining on the second image carrier.
JP 2003-316224 A JP-A-11-268363 JP 2000-280563 A

  However, in the image forming apparatus such as Patent Document 1, when the amount of toner in the waste toner container disposed on the second image carrier becomes full, the image forming apparatus is stopped and replaced with a new waste toner container. Alternatively, the accumulated waste toner needs to be discarded. Furthermore, in the image forming apparatus as disclosed in Patent Document 1, the waste toner container may become full despite such a complicated operation. When the tank is full, the image forming apparatus stops printing. Further, in the image forming apparatuses such as Patent Document 2 and Patent Document 3, it is necessary for the user to cut the sheet after printing, which is very complicated. Further, it is necessary to prepare a dedicated recording material for borderless printing. For this reason, plain paper cannot be used, the printing cost increases, and the type of sheet may be limited.

  The present invention has been made in view of the above-described problems. In an image forming apparatus capable of borderless printing, a developer image that matches the size and conveyance position of a recording material to be conveyed is formed, and waste toner is obtained. It aims at suppressing generation | occurrence | production of this.

The present invention relates to an image forming apparatus. The image forming apparatus includes a plurality of image carriers on which electrostatic latent images are formed, and an exposure unit that exposes each of the plurality of image carriers to form an electrostatic latent image on the plurality of image carriers. A plurality of developing members that respectively develop electrostatic latent images of the plurality of image carriers, a rotatable intermediate transfer belt on which a toner image is primarily transferred from the plurality of image carriers, and a transfer with the intermediate transfer belt A transfer member for secondary transfer of a toner image from the intermediate transfer belt to a recording material conveyed to the transfer unit, a control unit, and a recording material to the transfer unit at a predetermined timing An image forming apparatus capable of forming a toner image on a recording material without a border, and disposed upstream of the conveyance adjusting unit in the recording material conveyance direction. Of the recording material conveyed toward the adjusting means. A recording material detection unit configured to detect a length in the feeding direction, a length in a width direction orthogonal to the conveyance direction, and a conveyance position in the width direction, and forms a toner image without a border on the recording material; In this case, after the recording material detection unit detects the length in the conveyance direction of the recording material conveyed toward the conveyance adjustment unit, the length in the width direction orthogonal to the conveyance direction, and the conveyance position in the width direction, The exposure unit starts forming electrostatic latent images on the plurality of image carriers, and has a length in the conveyance direction of the recording material conveyed toward the conveyance adjustment unit detected by the recording material detection unit, the length in the width direction perpendicular to the conveying direction, an electrostatic latent image corresponding to the transport position in the width direction, and forming prior Symbol plurality image bearing member all.

  The present invention relates to an image forming apparatus capable of borderless printing, which forms a developer image that is aligned with the size and transport position of a recording material to be transported, and is capable of suppressing generation of waste toner as compared with the prior art. Can provide.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. The following embodiments do not limit the invention described in the claims, and all the combinations of features described in the embodiments are essential to the solution means of the present invention. Not exclusively.

  FIG. 1 is a cross-sectional view of an image forming apparatus according to the present invention. The image forming apparatus of the present invention includes an electrophotographic color image forming apparatus as an application example. Note that the image forming apparatus of the present embodiment employs an intermediate transfer method. Here, only the part related to the present invention will be described.

  The image forming apparatus 100 according to the present embodiment mainly includes four image forming units 102a, 102b, 102c, and 102d, an intermediate transfer belt 103, a secondary transfer unit 108, a waste toner container 112, and a component responsible for image formation. A fixing unit 115 is included. The image forming apparatus 100 includes a recording material detection unit 120, a paper size sensor 130, a conveyance path 124, and a registration roller 123 as components mainly responsible for conveyance of the recording material 101. Further, the image forming apparatus 100 includes an input device 122 for a user to input a control instruction regarding printing. The image forming apparatus 100 can be connected to a host computer 121 for inputting a printing instruction to the image forming apparatus 100.

  Since the four image forming units 102a, 102b, 102c, and 102d can adopt the same configuration, only one image forming unit will be described below. The image forming unit 102 includes a photosensitive drum 104 as an image carrier. Further, the photosensitive drum 104 is pivotally supported at the center thereof and is driven to rotate in the direction of the arrow as shown in FIG. Further, the image forming unit 102 is opposed to the outer peripheral surface of the photosensitive drum 104, and includes a primary charger 105, an exposure unit 106, a developing device 107 as a developer carrying member, and a primary transfer waste toner container 110 in the rotation direction. Including.

  During image formation, the image forming unit 102 forms a developer image on the photosensitive drum 104. Specifically, the image forming unit 102 applies a uniform charge amount to the surface of the photosensitive drum 104 by the primary charger 105. Next, the image forming unit 102 exposes a light beam such as a laser beam modulated according to the image signal input to the exposure unit 106 onto the photosensitive drum 104 via a folding mirror. When exposed, an electrostatic latent image is formed on the surface of the photosensitive drum 104.

  The developing device 107 contains toners (developers) of four colors of black, magenta, cyan, and yellow for each of the image forming units 102a, b, c, and d. The electrostatic latent images on the respective photosensitive drums 104 are developed into developer images of black, magenta, cyan, and yellow by the developing device 107, respectively.

  The photosensitive drum 104 is in contact with the intermediate transfer belt 103 to primarily transfer the developer image on the photosensitive drum 104 to the intermediate transfer belt 103. Thereafter, the toner remaining on the photosensitive drum 104 during the primary transfer is scraped off and cleaned by the primary transfer blade 109. The scraped toner is stored in the primary transfer waste toner container 110 as waste toner.

  The secondary transfer unit 108 secondarily transfers the developer image formed on the intermediate transfer belt 103 onto the recording material 101. Further, in the secondary transfer unit 108, two rollers are arranged opposite to each other with the intermediate transfer belt 103 interposed therebetween in order to secondary transfer the developer image to the recording material 101. These rollers are in pressure contact with the intermediate transfer belt 103 with an appropriate pressure, and secondarily transfer the developer image onto the recording material 101 that has been conveyed. Further, the toner remaining on the roller during the secondary transfer is scraped off by the secondary transfer blade 111 and stored in the secondary transfer waste toner container 112 as waste toner. Thereafter, the image formed on the recording material 101 is permanently fixed by the fixing unit 115.

  The recording material 101 is supplied from the storage cassette or the manual feed tray and is conveyed to the registration roller 123 through the conveyance path 124. The paper size sensor 130 outputs the paper size of the supplied recording material 101, for example, a size type such as A4 or B5. Thereafter, the registration roller 123 sends the recording material 101 to the secondary transfer unit 108 in synchronization with the image formation timing.

  Note that when borderless printing is selected, the image forming apparatus 100 determines the length of the recording material 101 to be conveyed in the main scanning direction, the length in the sub scanning direction, the conveyance position in the main scanning direction, and the conveyance in the sub scanning direction. The position is detected by the recording material detection unit 120. Here, the conveyance position in the main scanning direction is a position with respect to the conveyance path of the recording material 101 to be conveyed. That is, the transport position is a distance from a predetermined end of the transport path to a predetermined position of the recording material 101 transported. The predetermined position of the recording material 101 is, for example, the shortest end of the recording material 101 in the direction orthogonal to the transport direction from the end of the transport path. The transport position in the sub-scanning direction may be detected as long as the recording material 101 reaches the recording material detection unit 120. The length and transport position detected by the recording material detection unit 120 are used to align the developer image formed on the photosensitive drum 104 with the size and transport position of the recording material 101 to be transported. Note that the transport position in the sub-scanning direction is used to align the developer image formed on the intermediate transfer belt 103 and the leading end position of the recording material 101.

  Further, when printing with a border is selected, the image forming apparatus 100 detects the transport position in the sub-scanning direction with respect to the transport path 124 of the recording material 101 transported by the recording material detection unit 120. The detected transport position is used for registration processing that matches the position of the developer image formed on the intermediate transfer belt 103 and the recording material 101 by the secondary transfer unit 108.

  Hereinafter, the borderless printing operation of the image forming apparatus will be described. The image forming apparatus 100 starts a printing operation in accordance with an input from the input device 122 or the host computer 121. First, the image forming apparatus 100 feeds and transports the selected recording material 101. The fed recording material 101 is conveyed to the recording material detection unit 120. Further, the recording material 101 conveyed to the recording material detection unit 120 is conveyed on the recording material detection unit 120. When the recording material 101 is conveyed, the recording material detection unit 120 detects the length and conveyance position of the recording material 101 described above.

  When the length and transport position of the recording material are detected, the image forming apparatus 100 inputs an image signal for forming a developer image to the image forming unit 102 based on the information. Next, the exposure unit 106 exposes the photosensitive drum 104 in accordance with the input image signal to form an electrostatic latent image. When the electrostatic latent image is formed on the photosensitive drum 104, the developing device 107 develops the electrostatic latent image. The developed developer image is primarily transferred to the intermediate transfer belt 103 from the upstream image forming unit 102 a with respect to the rotation direction of the intermediate transfer belt 103. Thereafter, in accordance with the rotation of the intermediate transfer belt 103, developer images are sequentially formed in a multiple manner as in the image forming units 102b, 102c, and 102d.

  Note that the recording material 101 waits at the position of the registration roller 123 until the developer image is primarily transferred to the intermediate transfer belt 103 after the detection of the recording material 101 by the recording material detection unit 120 is completed. Become. Thereafter, the image forming apparatus 100 adjusts the conveyance speed of the recording material 101 with the registration roller 123 so that the primary transfer developer image and the leading edge of the recording material 101 are aligned at the secondary transfer unit 108. When the developer image on the intermediate transfer belt 103 is secondarily transferred onto the recording material 101, the developer image is fixed on the recording material 101 onto which the developer image has been secondarily transferred by the fixing unit 115, and the image forming apparatus 100. It is discharged outside.

  Next, the bordered printing operation of the image forming apparatus will be described. The image forming apparatus 100 starts a printing operation in accordance with an input from the input device 122 or the host computer 121. First, the image forming apparatus 100 feeds and transports the selected recording material 101. The paper size sensor 130 outputs the size type of the fed recording material 101 to the control unit. The image forming apparatus 100 inputs an image signal for forming a developer image based on the size type to the image forming unit 102. The exposure unit 106 exposes the photosensitive drum 104 in accordance with the input image signal to form an electrostatic latent image. Thereafter, as in the case of no border, the image forming unit 102 develops the electrostatic latent image and primarily transfers the developer image onto the intermediate transfer belt.

  On the other hand, the fed recording material 101 is conveyed to the recording material detector 120, and the conveyance position of the conveyed recording material 101 is detected. Thereafter, the image forming apparatus 100 performs a registration process based on the detected transport position, and secondarily transfers the developer image to the recording material 101. Further, the recording material 101 onto which the developer image has been secondarily transferred is fixed to the developer image by the fixing unit 115 and discharged to the outside of the image forming apparatus 100.

  FIG. 2 is a diagram illustrating a recording material detection method in the recording material detection unit. In the following description, information detected by the recording material detection unit 120 is detected mainly when borderless printing is selected.

  The recording material detection unit 120 includes recording material detection sensors 201A and 201B. According to the present embodiment, since it is necessary to detect the size and position more accurately than in the past, for example, an imaging element such as a CCD sensor or a C-MOS sensor is used as the recording material detection sensors 201A and 201B. Is preferred. Further, the recording material detection sensors 201A and 201B are arranged so as to be embedded on the main scanning line of the conveyance path 124 as shown in FIG.

  The recording material detection sensors 201A and 201B detect positions where the recording material 101 passes over the recording material detection sensors 201A and 201B. Output signals from the recording material detection sensors 201A and 201B are the length x in the main scanning direction, the length y in the sub scanning direction, the transport position X in the main scanning direction, and the transport position in the sub scanning direction of the recording material 101 being transported. Y is shown. The relationship between the output signal, the length of the recording material 101, and the transport position will be described later with reference to FIG.

  The lengths x and y and the transport positions X and Y detected by the recording material detection unit 120 represent the following contents. The length x in the main scanning direction represents the distance from Xs to Xe of the recording material 101. Further, the length y in the sub-scanning direction represents the distance from Ys to Ye of the recording material 101. The transport position X in the main scanning direction represents the distance from the reference line X0 that is the end of an arbitrary transport path 124 to the end on the longitudinal direction side that is close to the reference line X0 in the recording material 101 shown in FIG. Further, the transport position Y in the sub-scanning direction represents a distance from a reference line Y0 on the predetermined transport path 124 to a position at the leading end in the transport direction in the recording material 101.

  The transport position Y in the sub-scanning direction is detected even when bordered printing is selected. The information about the transport position Y in the sub-scanning direction is used for registration processing for aligning the position of the developer image formed on the intermediate transfer belt 103 and the recording material 101 in the secondary transfer at the secondary transfer unit 108. Used.

  The image forming apparatus 100 measures the size of the recording material to be conveyed and the conveyance position in more detail than before. This is to form a developer image substantially equal to the size of the recording material when borderless printing is selected. Note that there is a possibility that the size of the recording material can be specified from the type (A4, A3, etc.) of the recording material. However, for example, even with a recording material called A4 size, the actual size differs somewhat (for example, about 0.5 mm) depending on the manufacturer. Therefore, in order to reduce waste toner suitably, it is necessary for the image forming apparatus 100 to measure an accurate size of the conveyed recording material. Further, when the developer image is transferred to the recording material, for example, if the toner image is displaced even by 0.5 mm, toner remaining on the intermediate transfer member is generated. Therefore, the image forming apparatus needs to accurately align the developer image formation position with the conveyance position of the recording material to be conveyed. Therefore, it is desirable that the image forming apparatus measures the transport position of the transported recording material. As a secondary effect, the image forming apparatus can perform borderless printing even with a free-sized rectangular recording material.

  FIG. 3 is a diagram illustrating an output signal when the recording material detection unit detects the recording material. Here, the relationship between the output signal of the recording material detection unit 120, the length of the recording material 101, and the transport position will be described. In the graph shown in FIG. 3, the horizontal axis direction is time (t), and the output signals of the recording material detection sensors 201A and 201B respectively indicate values from Low (00h) to High (FFh).

  The recording material detection sensors 201A and 201B output signals other than 00h when the recording material 101 is conveyed onto the recording material detection sensors 210A and 201B. The output signal is, for example, an 8-bit analog signal as shown in FIG. The recording material detection sensor 201 outputs High (FFh) when the recording material 101 covers all over the recording material detection sensor 201, and outputs 80h, which is a half value of High, when covering the half area. The recording material detection sensor 201 outputs Low (00h) when the recording material 101 does not cover the recording material detection sensor 201 at all.

  3 represents the timing at which the leading edge of the recording material 101 reaches the recording material detection sensors 201A and 201B with respect to the conveyance direction. Also, β shown in FIG. 3 represents the timing at which the trailing edge of the recording material 101 reaches the recording material detection sensors 201A and 201B with respect to the transport direction. 3 are values in a state where the output signals of the recording material detection sensors 201A and 201B are stable. This is an output signal in a state where the leading end of the recording material 101 has passed over the recording material detection sensors 201A and 201B and the rear end has not yet reached. That is, from these values a and b, the length covered by the recording material 101 in the main scanning direction of each recording material detection sensor 201 is obtained.

  The conveyance position X in the main scanning direction is obtained from the covering length and the position of the recording material detection sensor 201 with respect to the conveyance path 124. The length x in the main scanning direction is obtained from the covering length and the distance between the recording material detection sensor 201A and the recording material detection sensor 201B. The length y in the sub-scanning direction is obtained from the time α to β and the conveyance speed of the recording material 101. Further, the transport position Y in the sub-scanning direction is determined by the time when the recording material 101 reaches the recording material detection sensor 201 from a predetermined position on the transport path 124. However, since the transport position Y in the sub-scanning direction is used for registration processing for aligning the positions of the leading edge of the recording material 101 and the leading edge of the developer image, it is only necessary to know the time when the leading edge of the recording material 101 is detected. Therefore, it is only necessary to know the time α shown in FIG.

[First Embodiment]
FIG. 4 is a block diagram illustrating control of the image forming apparatus according to the first embodiment. Here, only the elements related to the present invention will be described. That is, the image forming apparatus of the present invention is not limited to the elements shown in FIG. The image forming apparatus 100 according to the present embodiment adjusts the timing of outputting an image signal for forming a developer image input to the exposure unit 106. Accordingly, the image forming apparatus is characterized in that the size of the developer image is matched with the size of the recording material 101 and the formation position of the developer image is matched with the transport position of the recording material 101.

  Image forming apparatus 100 further includes a control board 401 and an image signal output unit 402. The control board 401 controls the image forming apparatus 100 and includes a matching unit 406 and a memory 405. Here, only elements related to the present invention will be described, and descriptions and drawings of other elements will be omitted. The image signal output unit 402 outputs an image signal for forming a developer image to the exposure unit 106. This image signal is composed of a plurality of pulses having a pulse width corresponding to the length of the developer image in the main scanning direction.

  The input device 122 inputs a selection unit 408 that selects whether to form a borderless image or a bordered image, and a formation position adjustment value in the main scanning direction and a formation position adjustment value in the sub-scanning direction. And an input unit 409. Note that the selection unit 408 and the input unit 409 may be included in the host computer 121. Further, the exposure unit 106 includes a laser driver IC 403 to which the image signal from the image signal output unit 402 is input and a laser diode 404 that exposes the photosensitive drum 104.

  When the borderless printing is selected by the selection unit 408, the alignment unit 401 receives information on the size and the conveyance position of the recording material 101 conveyed from the recording material detection unit 120. Next, the matching unit 406 adjusts the output timing of the image signal output from the image signal output unit 402 to the exposure unit 106 based on the input size and transport position of the recording material 101. Detailed output timing of the image signal will be described later with reference to FIG. The adjusted output timing is input to the image signal output unit 402. When the output timing is input, the image signal output unit 402 outputs the image signal to the exposure unit 106 according to the input output timing. That is, the output timing of the image signal is determined by the output signals of the recording material detection sensors 201A and 201B. When the image signal is input to the laser driver IC 403 in the exposure unit 106, the exposure unit 106 causes the laser diode 404 to emit light according to the input image signal. Thereby, the laser beam L is irradiated onto the photosensitive drum 104, and an electrostatic latent image is formed.

  Therefore, the electrostatic latent image is formed in alignment with the size and transport position of the recording material 101. The developer image is developed by the developing device 107 in accordance with the formed electrostatic latent image. For this reason, the image forming apparatus can suppress the generation of toner remaining after the secondary transfer onto the recording material 101. The memory 405 is a non-volatile memory, and may store a length x in the main scanning direction and a length y in the sub-scanning direction. In that case, the matching unit 406 can determine the output timing of the image signal using the stored information. However, since the recording materials of the same size type are slightly different depending on the manufacturer, it is desirable to store the recording material size for each manufacturer. Of course, the conveyance position of the recording material will need to be detected.

  When bordered printing is selected by the selection unit 408, the alignment unit 401 receives the size type of the recording material 101 fed from the paper size sensor. First, the matching unit 406 outputs the size type to the image signal output unit 402. Next, the image signal output unit 402 outputs an image signal to the exposure unit 106 according to the size type. When the image signal is input to the laser driver IC 403 in the exposure unit 106, the laser diode 404 emits light according to the input image signal. Thereby, the laser beam L is irradiated onto the photosensitive drum 104, and an electrostatic latent image is formed.

  FIG. 5 is a timing chart of image signals when borderless printing is selected in the first embodiment. / TOP indicates a reference signal in the sub-scanning direction, and / BD indicates a reference signal in the main scanning direction. The image signal is output from the image signal output unit 402 to the exposure unit 106 and includes a plurality of pulses having a pulse width corresponding to the length of the developer image in the main scanning direction.

  The image signal output unit 402 starts outputting the image signal after a timing corresponding to the distance of the transport position Y in the sub-scanning direction detected by the recording material detection unit 120 according to the reference signals / TOP and / BD has elapsed. To do. Further, the image signal output unit 402 outputs the first pulse having a pulse width corresponding to the length x in the main scanning direction after the timing corresponding to the transport position X in the main scanning direction has elapsed.

  After that, for each reference signal / BD in the main scanning direction, the image signal output unit 402 has a pulse width corresponding to the length x in the main scanning direction after the timing corresponding to the transport position X in the main scanning direction has elapsed. Output a pulse. The plurality of pulses are continuously output until a pulse corresponding to the length y of the recording material 101 in the sub-scanning direction is output after the first pulse is output.

  Thus, the image forming apparatus adjusts the output timing of the image signal output from the image signal output unit 402 based on the size of the recording material 101 detected by the recording material detection unit 120 and the transport position. Thereby, the formed developer image can be aligned with the size and transport position of the recording material 101.

  FIG. 6 is a timing chart showing the timing of image formation in borderless printing and bordered printing. Here, the driving timing of the conveyance motor for conveying the recording material 101, the timing at which the recording material detection sensor 201 detects the size and conveyance position of the recording material 101, the timing at which an image signal is output, and the recording material 101 The image forming timing will be described. The recording material 101 is conveyed by rotating rollers such as a paper feed roller and a registration roller 123 by controlling a conveyance motor.

  In the case of borderless printing, when feeding is started, the recording material detection unit 120 causes the recording material detection sensor 201 to detect the length x of the recording material 101 in the main scanning direction, the length y in the sub scanning direction, and the main scanning direction. The transport position X and the transport position Y in the sub-scanning direction are detected. In the case of borderless printing, an image signal is output based on the detection result of the recording material 101 by the recording material detection unit 120. Therefore, the output of the image signal is not performed until the detection of the recording material 101 is completed. The recording material 101 is subjected to a registration process in which the conveyance timing is adjusted at the position of the registration roller 123. In the registration process, the recording material 101 is stopped or decelerated at the position of the registration roller so that the leading edge of the developer image formed on the intermediate transfer member 103 and the leading edge of the recording material 101 are aligned by the secondary transfer unit 108. To be done.

  On the other hand, in the case of bordered printing, the recording material detection unit 120 does not need to detect the length x of the recording material 101 in the main scanning direction, the length y in the sub scanning direction, and the transport position X in the main scanning direction. This is because, in the case of printing with margins, there is a margin at the end of the recording material 101, and even if the formation position is slightly shifted, no waste toner is generated, so there is no need to detect the recording material 101 in detail. Therefore, when paper feeding is started, the image signal output unit 402 outputs an image signal according to the size type of the fed recording material 101. For this reason, printing with borders outputs an image signal almost simultaneously with feeding of the recording material 101 and forms a developer image, compared with borderless printing, so that the adjustment time at the registration roller 123 is shortened. Therefore, efficient printing processing is performed for bordered printing.

  FIG. 7 is a flowchart showing control until an electrostatic latent image is formed in the first embodiment. According to the first embodiment, the alignment unit 406 adjusts the timing at which an image signal is output based on the size or conveyance position of the recording material 101 detected by the recording material detection unit 120, and creates a developer image to be formed. The recording material 101 is matched with the size and the conveyance position.

  In step S <b> 701, the selection unit 408 transmits the borderless or bordered printing mode input from the user to the matching unit 406. When the print mode is selected, in step S702, the alignment unit 406 determines whether the print mode is borderless printing or bordered printing. If borderless printing is selected, in step S703, the alignment unit 406 acquires the size and the transport position of the recording material 101 detected by the recording material detection unit 120.

  Thereafter, in step S <b> 704, the matching unit 406 outputs a signal for adjusting the output start timing or output end timing of the image signal output from the image signal output unit 402 to the image signal output unit 402. The output start timing is determined from the transport position X in the main scanning direction and the transport position Y in the sub-scanning direction as described with reference to FIG. The output end timing is determined for each pulse from the length x in the main scanning direction, and the output end timing for the entire image signal is determined from the length y in the sub-scanning direction.

  When the output timing of the image signal is adjusted, in step S706, the image signal output unit 402 outputs the image signal to the exposure unit 106 according to the timing input from the matching unit 406. Finally, in step S707, the exposure unit 106 performs exposure scanning on the photosensitive drum 104 in accordance with the image signal output from the image signal output unit 402, thereby forming an electrostatic latent image.

  On the other hand, if bordered printing is selected, the alignment unit 406 acquires the size type of the recording material 101 from the paper size sensor 130 in step S705. The matching unit 406 transmits the acquired size type to the image signal output unit 402. Thereafter, in steps S706 and S707, the same processing as in the case of borderless printing is performed.

  As described above, the image forming apparatus according to the present embodiment includes a selection unit that selects whether an image is formed without a border or with a border on a recording material. The image forming apparatus also includes a main scanning direction length, a sub scanning direction length, a transport position in the main scanning direction, and a sub scanning direction with respect to the recording material to be transported when borderless is selected by the selection unit. Includes a recording material detection unit for detecting the transport position. In addition, the image forming apparatus matches the image size of the developer image formed on the recording material with the size of the recording material based on the detected length and the transport position, and the developer image forming position is adjusted. And an alignment unit for aligning the conveyance path with the conveyance position of the recording material conveyed. Further, the image forming apparatus includes an image forming unit that forms a developer image on the recording material in accordance with the image size and the forming position aligned by the aligning unit. Accordingly, when the borderless printing is selected, the image forming apparatus is provided on the intermediate transfer belt when the image is formed on the recording material in order to align the developer image to be formed with the size and transport position of the recording material. The toner to be used can be reduced. As a result, the image forming apparatus does not form a developer image larger than the recording material in the case of borderless printing, so that the toner consumption can be reduced and the generation of waste toner can be suppressed.

  The present invention is not limited to the above embodiment, and various modifications are possible. For example, the image forming unit is an image signal for forming an image carrier and a developer image, and is composed of a plurality of pulses having a pulse width corresponding to the length of the developer image in the main scanning direction. May be included. Further, the image forming unit may include an exposure unit that forms an electrostatic latent image by performing exposure scanning on the image carrier in accordance with the image signal and the image size and the formation position aligned by the alignment unit. . Further, the image forming unit may include a developer carrier that develops an electrostatic latent image formed on the image carrier with a developer to form a developer image. Therefore, the present image forming apparatus is aligned with the size and the transport position of the recording material at the time when the electrostatic latent image is formed, so that it is not necessary to consume extra toner. Therefore, this image forming apparatus can reduce the toner consumption and suppress the generation of waste toner.

  The alignment unit adjusts the output start timing for each pulse in the image signal based on the detected conveyance position of the recording material, and outputs the output for each pulse in the image signal based on the detected length of the recording material. The end timing may be adjusted. In this case, the image signal output unit may output the image signal to the exposure unit in accordance with the adjusted output start timing and output end timing. Therefore, the image forming apparatus is adjusted to the size and the transport position of the recording material at the time when the electrostatic latent image is formed by adjusting the image signal, so that it is not necessary to consume extra toner. Therefore, this image forming apparatus can reduce the toner consumption and suppress the generation of waste toner.

  The recording material detection unit omits at least detection of the length of the recording material in the main scanning direction, the length in the sub-scanning direction, and the conveyance position in the main scanning direction when the presence of a border is selected. May be. Therefore, when no margin is selected, the image forming apparatus reduces the toner consumption and suppresses the generation of waste toner by accurately detecting the size and the transport position of the recording material. However, this image forming apparatus can execute efficient printing in order to simplify the detection of the recording material by the recording material detection unit when the presence of border is selected.

  Further, the image forming unit may start forming the electrostatic latent image before the conveyance position of the recording material in the sub-scanning direction is detected when the presence of the edge is selected. Further, after the transport position in the sub-scanning direction is detected, the image forming unit performs a registration process that matches the transport position of the developer image in the sub-scanning direction with the transport position of the recording material in the sub-scanning direction. It may be. Therefore, when the presence of edge is selected, the image forming apparatus starts forming an electrostatic latent image as soon as paper feeding is started. Therefore, the period during which conveyance of the recording material is stopped or developed by adjustment by the registration process Will be suppressed. Therefore, when the presence of edge is selected, the image forming apparatus can execute efficient printing.

[Second Embodiment]
FIG. 8 is a block diagram illustrating the control of the image forming apparatus according to the second embodiment. Here, only the elements related to the present invention will be described. The image forming apparatus 100 according to the present embodiment masks an image signal for forming a developer image input to the exposure unit 106. Accordingly, the image forming apparatus is characterized in that the size of the developer image is matched with the size of the recording material 101 and the formation position of the developer image is matched with the transport position of the recording material 101. Here, only elements that are different from the image forming apparatus according to the first embodiment are described in order to avoid duplication of explanation.

  When borderless printing is selected by the selection unit 408, the matching unit 406 transmits the size type of the recording material 101 input from the paper size sensor 130 to the image signal output unit 402. The image signal output unit 402 outputs an image signal for forming a developer image larger than the size type to the exposure unit 106 according to the input size type. The matching unit 406 outputs a mask signal for masking the image signal in accordance with the image signal output from the image signal output unit 402 to the exposure unit 106.

  This mask signal is generated from the length x of the recording material 101 in the main scanning direction, the length y in the sub scanning direction, the transport position X in the main scanning direction, and the transport position Y in the sub scanning direction. Note that the image signal output from the image signal output unit 402 partially extracts pulses that overlap the mask signal. That is, the mask signal is a signal that excludes a part of the pulse corresponding to the developer image formed beyond the detected size and transport position of the recording material 101. Therefore, the exposure unit 106 starts exposure to the photosensitive drum 104 when an image signal is input, and adjusts the start or stop of light emission in the laser diode 404 by this mask signal. As a result, the electrostatic latent image is formed on the photosensitive drum 104 in alignment with the size and transport position of the recording material 101.

  FIG. 9 is a timing chart of an image signal and a mask signal when borderless printing is selected in the second embodiment. / TOP indicates a reference signal in the sub-scanning direction, and / BD indicates a reference signal in the main scanning direction. The image signal is output from the image signal output unit 402 to the exposure unit 106 and includes a plurality of pulses having a pulse width corresponding to the length of the developer image in the main scanning direction. The mask signal is output from the matching unit 406 to the exposure unit 106 to mask the image signal. The formation timing indicates the timing at which the laser diode 404 actually emits light by the image signal and the mask signal.

  The image signal output unit 402 outputs to the exposure unit 106 an image signal that forms a developer image larger than the size of the recording material 101 in accordance with the reference signals / TOP and / BD. In addition, the matching unit 406 outputs a mask signal for masking the image signal to the exposure unit 106. First, after the timing corresponding to the transport position Y in the sub-scanning direction and the transport position X in the main scanning direction has elapsed, the alignment unit 406 outputs the first mask signal having a width corresponding to the length x in the main scanning direction. To do.

  After that, for each reference signal / BD in the main scanning direction, the alignment unit 406 outputs a mask signal having a width corresponding to the length x in the main scanning direction after a timing corresponding to the transport position X in the main scanning direction has elapsed. To do. This mask signal is output until the timing corresponding to the length y of the recording material 101 in the sub-scanning direction elapses after the first mask signal is output. When the mask signal is output, as shown in FIG. 9, a part of the pulse output at the same timing as the mask signal is extracted from the image signal.

  As described above, the image forming apparatus masks the image signal output from the image signal output unit 402 based on the size of the recording material 101 detected by the recording material detection unit 120 and the transport position. Thereby, the formed developer image can be aligned with the size and transport position of the recording material 101.

  FIG. 10 is a flowchart showing control until an electrostatic latent image is formed in the second embodiment. According to the second embodiment, the aligning unit 406 generates a mask signal that masks the image signal based on the size or conveyance position of the recording material 101 detected by the recording material detection unit 120, and forms a developer image. Are aligned with the size and transport position of the recording material 101.

  Note that technical matters common to the first embodiment are omitted to avoid repeated description. For example, steps S1001 and S1002 correspond to the above-described S701 and S702, and thus description thereof is omitted. When printing with a border is selected, the image forming apparatus according to the present embodiment performs the same operation as that of the first embodiment. Therefore, the description is omitted. Therefore, in the following description, only steps S1004 and S1005 will be described.

  When borderless printing is selected by the user, the alignment unit 406 generates a mask signal that masks the image signal output from the image signal output unit 402 in step S1004. Further, as described with reference to FIG. 9, the mask signal is generated based on the size and the transport position of the recording material 101 detected by the recording material detection unit 120.

  Next, in step S1005, the image signal output unit 402 and the matching unit 406 output an image signal and a mask signal, respectively. Note that the image signal and the mask signal are preferably output in a synchronized state. The image signal output unit 402 outputs an image signal for forming a developer image larger than the size type of the recording material 101.

  The matching unit 406 may output a mask signal before the image signal is output. In that case, the exposure unit 106 may need to hold the mask signal until the image signal is output by the image signal output unit 402 and to synchronize the mask signal in accordance with the output of the image signal.

  As described above, according to the image signal output unit according to the present embodiment, an image signal that forms a developer image having a size larger than the size of the recording material is output to the exposure unit. Further, the alignment unit forms an electrostatic latent image exceeding the size of the recording material among the pulses included in the image signal based on the detected length of the recording material and the transport position of the recording material. A mask signal for masking the pulse portion is output. Further, the exposure unit exposes the image carrier in accordance with the image signal masked according to the mask signal. Therefore, since the image forming apparatus is aligned with the size and the transport position of the recording material at the time when the electrostatic latent image is formed by masking the image signal, it is not necessary to consume extra toner. . Therefore, this image forming apparatus can reduce the toner consumption and suppress the generation of waste toner.

[Third Embodiment]
FIG. 11 is a flowchart illustrating control until an electrostatic latent image is formed in the third embodiment. According to the third embodiment, the alignment unit 406 includes the size or conveyance position of the recording material 101 detected by the recording material detection unit 120, and the adjustment value of the developer image formation position input from the input unit 409. Is entered. Based on the two pieces of input information, the aligning unit 406 aligns the developer image to be formed with the size and transport position of the recording material 101.

  Further, this embodiment can be implemented in combination with the first embodiment or the second embodiment. Here, the form in the case of combining with the first embodiment will be described. Note that technical matters common to the first embodiment are omitted to avoid repeated description. For example, steps S1101 and S1102 correspond to the above-described S701 and S702, and thus description thereof is omitted. When printing with a border is selected, the image forming apparatus according to the present embodiment performs the same operation as that of the first embodiment. Therefore, the description is omitted. Therefore, in the following description, only steps S1103 and S1105 will be described.

  When borderless printing is selected by the user, in step S1103, the alignment unit 406 acquires the formation positions in the main scanning direction and the sub-scanning direction in the developer image input by the user from the input unit 409. In step S1104, the matching unit 406 acquires the size and the transport position of the recording material 101 detected by the recording material detection unit 120, as in the first embodiment.

  Next, in step S1105, the alignment unit 406 first aligns the size and formation position of the developer image with the size and conveyance position of the recording material 101 based on the detected size and conveyance position. Furthermore, the matching unit 406 finely adjusts the output start timing of the image signal based on the input adjustment value. For example, the matching unit 406 may adjust the sub-scanning direction reference signal and the main scanning direction reference signal shown in FIG. 5 based on the input adjustment values.

  For the sake of specific explanation, here, for example, it is assumed that the formed image is shifted 0.5 mm to the right with respect to the conveyance direction of the recording material 101. In this case, the user inputs an adjustment value for the formation position in the main scanning direction. As an input method, for example, an input for shifting the image to be formed by 0.5 mm to the left is performed. The matching unit 406 adjusts the image signal output unit 402 so as to speed up the output of the reference signal / BD in the main scanning direction shown in FIG. 5 in accordance with a user input. In addition, the timing to advance becomes a timing equivalent to 0.5 mm.

  As described above, the image forming apparatus according to the present embodiment may further include an input unit that inputs at least one of the adjustment value of the formation position in the main scanning direction and the adjustment value of the formation position in the sub-scanning direction. . In this case, the aligning unit aligns the image size of the developer image with the size of the recording material based on the detected length and conveyance position of the recording material and the input adjustment value, and the developer image The formation position may be aligned with the recording material. Therefore, the image forming apparatus can perform fine adjustment by user input when a defect occurs in which the image formed on the recording material is shifted during borderless printing. As a result, the image forming apparatus will further improve the accuracy in borderless printing. Therefore, this image forming apparatus can reduce the toner consumption and suppress the generation of waste toner.

1 is a cross-sectional view of an image forming apparatus according to the present invention. It is a figure which shows the detection method of the recording material in a recording material detection part. It is a figure which shows an output signal when a recording material detection part detects a recording material. FIG. 3 is a block diagram illustrating control of the image forming apparatus according to the first embodiment. 6 is a timing chart of an image signal when borderless printing is selected in the first embodiment. 6 is a timing chart showing image formation timing in borderless printing and bordered printing. 5 is a flowchart illustrating control until an electrostatic latent image is formed in the first embodiment. FIG. 10 is a block diagram illustrating control of an image forming apparatus according to a second embodiment. 10 is a timing chart of an image signal and a mask signal when borderless printing is selected in the second embodiment. 10 is a flowchart illustrating control until an electrostatic latent image is formed in the second embodiment. 10 is a flowchart illustrating control until an electrostatic latent image is formed in the third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100: Image forming apparatus 104: Photosensitive drum 120: Recording material detection part 122: Input device 130: Paper size sensor 201A, 201B: Recording material detection sensor 401: Control board 402: Image signal output part 403: Laser driver IC
404: Laser diode 405: Memory 406: Matching unit 408: Selection unit 409: Input unit

Claims (2)

A plurality of image carriers on which electrostatic latent images are formed; an exposure unit that exposes each of the plurality of image carriers to form electrostatic latent images on the plurality of image carriers; and the plurality of image carriers. Forming a plurality of developing members for respectively developing the electrostatic latent image on the body, a rotatable intermediate transfer belt on which a toner image is primarily transferred from the plurality of image carriers, and forming a transfer portion with the intermediate transfer belt, A transfer member for secondary transfer of the toner image from the intermediate transfer belt to the recording material conveyed by the transfer unit, a control unit, and a conveyance adjusting unit for conveying the recording material to the transfer unit at a predetermined timing; In an image forming apparatus capable of forming a toner image without a border on a recording material,
The length in the conveyance direction of the recording material that is arranged upstream of the conveyance adjustment unit in the conveyance direction of the recording material and is conveyed toward the conveyance adjustment unit, the length in the width direction orthogonal to the conveyance direction, and the width direction A recording material detection unit for detecting
When a toner image is formed without a border on a recording material, a length in the transport direction of the recording material transported by the recording material detection unit toward the transport adjustment unit, and a length in a width direction orthogonal to the transport direction After the conveyance position in the width direction is detected, the exposure unit starts to form an electrostatic latent image on the plurality of image carriers and faces the conveyance adjustment unit detected by the recording material detection unit. the length in the conveying direction of the recording material conveyed, the length in the width direction perpendicular to the conveying direction, an electrostatic latent image corresponding to the transport position in the width direction, be formed before Symbol plurality image bearing members all An image forming apparatus. The conveyance adjustment unit detects a length in a conveyance direction of a recording material conveyed by the recording material detection unit toward the conveyance adjustment unit, a length in a width direction orthogonal to the conveyance direction, and a conveyance position in the width direction. after, in order to convey the recording material to the transfer portion at predetermined timing, an image forming apparatus according to claim 1, characterized in that stop or slow down the transport of the recording material.

Images